Download telegram stickers and convert to PNG/GIF with optimizations

get-telegram-sticers.sh

#!/usr/bin/env bash

# Download telegram stickers and convert to PNG/GIF
#
# Dependecies:
# - jq, curl
# - https://www.ffmpeg.org/
# - https://pngquant.org/
# - http://www.lcdf.org/gifsicle/
# - https://github.com/ed-asriyan/lottie-converter
#
# TOKEN=123456 ./this https://t.me/addstickers/HANGSEED_Pepe Pepetopanim spinningfood notxxx

set -euo pipefail

: "${TOKEN:?Get token from @BotFather adn set to var}"
: "${name:-${1:?Specify the stickerpack name or url}}"

# WebP -> PNG
convert::webp () {
  < /dev/null ffmpeg -y -hide_banner -loglevel error -i "$1" "${1%.*}.png"
  rm -f "$1"

  pngquant --force --skip-if-larger --strip "${1%.*}.png"
  [ -f "${1%.*}-fs8.png" ] && \
    mv "${1%.*}-fs8.png" "${1%.*}.png"
}

# WebM -> GIF
convert::webm () {
  < /dev/null ffmpeg -y -hide_banner -loglevel error -i "$1" \
    -lavfi fps=10,palettegen "${1%.*}.palette.png"
  # TODO transparency not work
  < /dev/null ffmpeg -y -hide_banner -loglevel error -i "$1" \
    -i "${1%.*}.palette.png" -lavfi "fps=10,paletteuse=alpha_threshold=0" \
    -gifflags -offsetting "${1%.*}.gif"
  rm -f "$1" "${1%.*}.palette.png"

  gifsicle --batch -O3 -i -f "${1%.*}.gif"
}

# TGS -> GIF
convert::tgs () {
  local tmp="${1%.*}_tmp"

  mkdir -p "$tmp"
  gunzip -c "$1" > "$tmp/anim.json"
  lottie_to_png --output "$tmp" "$tmp/anim.json"

  < /dev/null ffmpeg -y -hide_banner -loglevel error -i "$tmp/%03d.png" \
    -vf palettegen=reserve_transparent=1 "$tmp/palette.png"
  < /dev/null ffmpeg -y -hide_banner -loglevel error -i "$tmp/%03d.png" \
    -i "$tmp/palette.png" -lavfi paletteuse=alpha_threshold=128 \
    -gifflags -offsetting "${1%.*}.gif"
  rm -r "$1" "$tmp"

  gifsicle --batch -O3 -i -f "${1%.*}.gif"
}

mkdir -p "stickers"

for pack in "$@"; do
  pack="${pack##*/}"
  mkdir -p "stickers/$pack"

  while IFS=$'\t' read -r file_id width height emoji animated video id _; do
    echo "Proces: $id $emoji ${width}x$height in pack $pack"

    file_path=$(
      curl -sSfL "https://api.telegram.org/bot$TOKEN/getFile" \
        -F file_id="$file_id" | \
      jq -er '.result.file_path'
    )
    result_file="stickers/$pack/${file_path##*/}"

    curl -sSfL "https://api.telegram.org/file/bot$TOKEN/$file_path" -o \
      "$result_file"

    if [ "$video" == true ]; then
      convert::webm "$result_file"
    elif [ "$animated" == true ] ; then
      convert::tgs "$result_file"
    else
      convert::webp "$result_file"
    fi

  done < <(
    curl -sSfL "https://api.telegram.org/bot$TOKEN/getStickerset" \
      -F "name=$pack" | \
    jq -er '
      .result.stickers[] | [
        .file_id, .width, .height, .emoji,
        .is_animated, .is_video, .file_unique_id
      ] | @tsv' | \
    tr -d '\r'
  )
done